Conductor for wireless telegraphy.



Patented Aug. l2, i902..

INVENTOR (Application filed May 29. 1901.)

R. A. FESSENDEN. CNDUCTDR FUR WIRELESS TELEGRAPHY.

UNITED STATES PATENT OFFICE.

REGINALD 1A. ,lFEssENpEN, or ALLEei-IENY, PENNSYLVANIA.

CONDUCTOR FOR WIRELESS TELlaoRArl-lv.l

SPECIFICATION forming part of Letters Patent N o. 706,739, dated August 12, 1902.

Applicants tied May 29, 1901.

To ctZZ whom,4 t may concern:

Be it known that I, REGINALD A. FEssEN- DEN, a citizen ofthe UnitedStates, `residing at Allegheny, in'the` countyof Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in Conductors for Wireless Telegraphy, of Which improvements the following is a specication. p

It is generally believed that conductors of a considerable length are necessary for the eicient production of electromagnetic Waves. By the term electromagnetic Waves .as used herein is meant Waves of a Wave length long in comparison With the Wave length of what are commonly called heat-Waves or radiant heat. By `fgrounded conductor is meant a conductor grounded either directly or through a capacity, an inductance, or aresistance, so that the current in the conductor flows from the conductor to ground, and vice versa, When electromagnetic Waves are generated. The terms tuned and resonant are used herein as one including the other. Such impression is, however, erroneous, as I have discovered that by generating the Waves in a medium Whose permeability to electromagnetic waves or specific inductive capacity, or both, are greater than that of air short conductors may be used for the purpose of propagating and receiving electromagnetic Waves. Where one of the constants only isl increased, the same general effectsy are produced-as, for example, Where the conductor is immersed in Water so pure as to be nonconducting, in alcohol, or other substances having large specific inductive capacity the periodicity is decreased compared With that of the sameconductor in air, and radiation is increased thereby, giving the effect of long conductor.

In the accompanying drawings, forming part of this specification, Figure l is a sectional elevation of my improved conductor for Wireless telegraphy. Fig. 2 is a sectional view of the same. Figs. 3, 4, and 5 are sectional elevations illustrating lnodiflcations of the conductor, and Fig. 6 is a plan view of the form as shown in Fig. 5.

In the practice of my invention I preferably employ at the sending-station a conductor l,

Serial No. 62,306. (No model.)

having a large capacity and low self-indue tion. The capacity can be regulated by ncreasing the surface or area of the conductor and theself-induction by turns or coils in the Wire connecting the conductor to the generator, Which may be an induction apparatus or an alternating generator. A medium 2, consisting of Wire or lamina formed of magnetic material, as iron or-nickel, is arranged adjacent to the conductor on the side facing the direction of the receiving-station. The Wires forming the medium are arranged in coils, turns, or folds, as shown. Good results have been obtained by the employment of No. 40 B.A da S. insulated Wires. It is ,preferred that the wire, especially whenfformed of nickel, should be Wound and maintained under tension.'` The coils, turns, or folds,vvhich may bev arranged indiscriminately, asshown in Figs. l and 3, or may be arranged to form a single layer, as in Fig. 5, are spaced a distance apart less than the diameter of the wire and preferably a distance approximately equal to one-fourth the diameter of the `Wire and are insulated from each other. The insulation of the coils, turns, or folds can be conveniently effected by filling the spaces or surrounding Wire With an insulating material preferably of high specic inductive capacity, such as india-rubber, Water, alcohol, paran, &c. The medium may entirely sur,- round. the conductor, as shown in Fig. l, or be arranged only on the side facing the receiving-station, as shown in Figs. 5 and 6. If the conductor; be surrounded by a medium having the coils, turns, or loops spaced a distance apart equaLor. approximately equal to one-fourth (@-the diameter of the wire and embedded in rubberof specific inductive capacity four, the virtual specic inductive capacity of' thev medium will be approximately Y ICO T 2 yr C L The capacity of a conductor depends, among other things, upon the specific inductive capacity of the medium surrounding it and varies directly as this specific inductive capacity. The inductance of a conductor depends, among other things, on the permeability of the medium surrounding it and varies directly as this permeability.

'Thus it follows that since the period T of the Waves frmed in the medium described will be 15 X 900 120 times as great as the period of waves formed by the same conductor in air. Now the velocity of electromagnetic 4 l Waves in a medium is V Mk-Mwhere k is the dielectric constant or specific inductive capacity and ,u is the permeability of the medium; but as I have made kequal sixteen times that of air and ,u equal nine hundred times that of air, it follows that the Velocity of the travel of Waves in this medium will be V 15 X 90() 120 of that in air; but in any wave propagation the Velocity equals V n 7l, where n equals the frequency and )t equals the wave length. Hence, as I have decreased the velocity to one one-hundred-andtwentieth of its value in air and have also decreased the frequency so that one one-hundred-and-twentieth of the value it would have if the medium I have described were not V n used- 71. e., 120 y120 7l--it follows that the length of the waves in the medium will be the same as the length of wave generated by the same conductor when surrounded by air. Now it is a well-known principle in optics that if a wave emerges from a denser medium to one less dense the length of such wave is increased in proportion to the ratio of the speeds of the wave in the two media. So it is also in electroptics. Hence as the waves pass from the medium in which its speed is one one-hundred-and-twentieth of its speed in air the wave length increases one hundred and twenty times. Hence a conductor one foot in length s urrounded by and generating waves through such a medium willgenerate be used having, for example, a specific inductive capacity sixty-four, the virtual specific inductive capacity with the same distance between the lines as before would be approximately four multiplied by sixty-four, and hence the waves in the medium would now be 'V256X900=960 times the length which the same conductor would produce in air. Similarly if the iron Wire were of a poorer grade magnetically or were less permeable to magnetic forces of a high frequency its virtual permeability might be only one hundred, and if the same insulating material as in the last case were used `the wave length would be `/l0O 256=160 times the wave length produced by the same conductor in air. It will thus be seen that if a conductor in air having a certain self-inductance and capacity be surrounded by such a medium its self-inductance and capacity, or both, are increased. Since the wave length generated by the conductor depends upon the square root of the;

product ot these two factors, it will be seen that the wave length from a given conductor can be increased by surrounding it by such a medium. Also since the energy when the conductor is charged varies for a given voltage directly with the capacity by increasing the capacity the energy available for radiation has been increased; and, further, with a given capacity the energy radiated depends upon the proportion which the wave length bears to the height of the conductor. Hence merely increasing the capacity of a conductor surrounded by air by increasing its surface without altering its height does not increase the radiation to the same extent as does increasing its capacity byincreasingits height. In the present case, however, it is possible to increase the capacity of the conductor without altering its height and yet without altering the relation between the wave length and the medium and the height Vof the conductor-in other words, to obtain the same eect as is produced in air by raising the height of the conductor.

In the practice .of my'invention, except where it is desired for special purposes, to obtain as long wave lengths as possible it is preferred to use a medium having large speciic inductive capacity and small permeability.

For some purposes-6. g., where it is desired that the waves should have a high eficiency in one direction oron one side of the conductor-the medium may be arranged on the side of the conductor facing the point toward which the waves are to be principally eective, as shown in Figs. 5 and 6. An incremental effectiveness may be produced by the employment of a reiiecting-plate 3, which is formed of metal arranged on the side of the conductor opposite that facing the direction in which the waves are to travel. The

employment of a reiector for the purpose of concentrating and projecting the waves is practically possib'leonly with short conductors. The dimensions, shape, and position of the reiiector will ybe varied in accordance with the conditions under which it is used. In general it is desirable to arrange the reflector so as to form a portion of the outer Wall of the medium.

When using an induction apparatus for charging and discharging the conductor, one end of the latter is connected to a knob 4, forming one side of the spark-gap, while the other knob is connected to ground. When using a dynamo or other source of alternating current, one terminal of the generator is connected to the conductor and the opposite terminal to ground.

It is preferredk thaty the electromagnetic waves travel along or near the surface of the earthand that the generation ofthe waves should occur closely adjacent to the surface ofthe earth, thereby increasing their efficiency. To this end the conductor l, which may be a wire, as shown, or may be in the form of a cylinder, as shown in Fig. l, or a plate or sheet, as shown in Figs. 5 and 6, is arranged horizontally, or approximately so, as shown in Fig. 3; but this construction forms no part of the subject-matter herein. One ofthe sparking-knobs is connected to the conductorl la, preferably at a point midway of its length,'as shown. 'Self-inductance coils 5 may be interposed between the conductor and knob to change the natural oscillation period of the system. The other sparking-knob is connected to a cone 6, formed of metal or other conducting material and arranged below the conductor. This cone may be arranged on a table or other supportand connected toground and -may rest directly on the ground. In order to increase the efficiency of the conductor as regards the distance of travel of the Waves, a medium 2- such, for example, as that heretofore de-g,

scribed-is interposed between the conductor and cone. This medium may be made annular and extend entirely around the cone or'f` may extendv only partially around the cone, on that side where the waves should be most The waves as they pass through. the medium impinge on. the surface of ^the,v cone and are deflected down lonto and along.

efficient.

the surface of the earth. y As shown in Fig. 4t, a second conductor, instead of an electrical image, as it` might be termed, can be employed. In such case two similar conductors l are connected to op-v` posite poles of the generating apparatus, and when an induction apparatus is used the spark-gap is formed between theconductors,

the knobs 4 being connected to adjacent ends of the conductors. It is preferred that vthe conductors be surrounded either entirelyor partially, as heretoforedescribed, by a medium 2. y f' The employment of a-rnedium in the manner described permits of the generation of 7erection and maintenance of high masts. ;=has, however, another property, in that not only is the wave length the same as that from la long wire, but also the amount of energy tion.'

electromagnetic waves4 of different periodicities from the same conductor as the periodicity of a wave is dependent upon the permeability and specific inductive capacity, or both,

.of the medium in which itis generated. As,

for example, if the medium 2 be arranged in such relation to the conductor that the waves from a portion of the surface of the conductorpass through the medium, while the waves from other portions of the surface are generated and pass directly through the air, the

-twosets of waves will have'different perio- .mediate of its ends., This may be effected by enlarging the conductor at the desired portion or portions, as by a swell integral with the walls of the conductor or by aband or. bands 7wof conducting material surrounding the conductor and in metallic contact therewith. This latter construction affords means for adjusting the capacity by addingorA removing bands or changing the position thereof along'the conductor. would generate two or more series of waves of different periodicities, the periodicity of one series of waves being dependent upon the length and configuration of the conductor andthe periodicity or periodicities of the other series upon the bands or enlargements.

This form of conductor thus enables me to obtain long waves from a short conductor, thereby avoiding the expense involved in the It radiated is the same for a given difference of potential as from ahigh wire. In other words, it is characteristic of this improvement that all the functions or desirable results incident to the employment of a long high conductor can be attained by a-relatively short low con- Such a conductor IOO IIO

ductor and with the additional and many ad- I vantages peculiar to this conductor-e. g., it assists me in obtaining a construction which forms one of the objects of the invention embodied in application Serial No. 62,301, tiled May 29, l 901.

The receiving-stations may have a conductor similar to that described, or plain conductors tuned to receive the several series vof waves may be employed at the receiving-sta- It has been suggestedin wireless-telegraphy. work to employ `apparatus in which the sparking terminals have been immersed in a liquid insulator of greater specific inductive capacity than air; but this'was done for the purpose of obtaining a more abrupt spark, and not 'for the purpose of obtaining a greater length of wave fromagiven conductor. Moreover, as employed, while it would serve the purpose for which it was intended-7l. e., better insulation of the terminals and more abrupt spark-it would not when used as dero scribed produce the effect aimedat in the /preseut application.

I claim herein as my inventionl. A conductor for radiating electromagnetic waves, in combination with a medium I 5 having an electrical constant on which the wave length depends of a v'alue greater than that of air arranged in suitable relation to the conductor.

2. A conductor for radiating electromag- 2o netic waves havingin combination therewith, a medium having an electrical constant on which the wave length depends of a value greater than that of air, arranged around the conductor, substantially as set forth. i

3. A conductor for radiating electromagnetic waves in combination with a medium consisting of lamina of insulated magnetic material arranged in suitable operative relation to the conductor, substantially as set forth.

f1. A conductor for radiating electromagnetic Waves in combination with a medium consisting of lamina or wire of magnetic material and a material of higher specific inductive capacity than that of air, filling the spaces between the lamina of conducting material, substantially as set forth.

5. A conductor for radiating electromagnetic waves in combination with a medium having an electrical constant on which the wave length depends of a value greater than that of air and means for causing an incremental effectivenessin a given direction, substantially as set forth.

6. A conductor for radiating electromagnetic waves in combination with a medium having an electrical constant on which the wave length depends of a value greater than that of air and a reflector whereby the waves generated by the conductor may be concentrated and projected in a given direction, substantially as set forth.

7. A conductor for radiating electromagnetic waves in combination with means whereby a different periodicity is imparted to the waves generated from dierent portions of the conductor, and a medium having an electrical constant on which the wave length depends of a value greater than that of air arranged in suitable relation to the conductor, substantially as set forth.

S. A conductor for radiating electromagnetic waves in combination with a piece of conducting material arranged on the conductor, 65 and a medium having an electrical constant on which the wave length depends of a value greater than'tha't of air arranged in suitable relation to the conductor, substantially as set forth.

9. A conductor for wireless telegraphy in combinationwith a movable piece of conducting material arranged on the conductor, substantially asset forth.

10. A conductor for radiating electromagnetic waves, surrounded by a medium in which the wave length of electromagnetic radiation is less than the wave length of the same radiation in air, substantially as set forth.

ll. A conductor for radiating electromagnetic waves, in combination with a movable piece of conducting material so arranged and proportioned that the system will simultaneously radiate waves of dierent periodicities of approximately the same energy, substantially as set forth. l

12. A conductor for radiating electromagnetic waves, having a substantially uniform capacity over a large portion of its length and a piece of conducting material connected to such portion, whereby waves of different periodicities but of approximately the same energy may be'radiated, substantially as set forth.

13. The combination of a vertically arranged Aconductor for wireless telegraphy and a medium substantially as described arranged in operative relation to the conductor, substantially as set forth.

14. 'The combination of a conductor for radiating electromagnetic waves connected to ground and a medium having an electrical constant on which the wave length depends of a value greater than that of air arranged in operative relation to the conductor, substantially as set forth.

15. A grounded conductor for radiating electromagnetic waves in combination with a medium having an electrical constant on which the wave length depends, of a value greater than that of air, arranged in suitable relation to the conductor.

16. A grounded conductor for wireless telegraphy, having in combination therewith a lmedium having an electrical constant on which the wave length depends, of a Value greater than that of air, arranged around the conductor, substantially as set forth.

17. A grounded conductor for wireless telegraphy, having in combination therewith a medium consisting of lamina of insulated magnetic material arranged in suitable operative relation to the conductor, substantially as set forth. j

18. A grounded conductor for Wireless telegraphy, in combination with means whereby a different periodicity is imparted to the waves generated from different portions of the conductor, and a medium having electrical constant on which the wave length depends,

IOO

IIO

of a value greater than that of air, arranged etio Waves, and a medium substantially'as 1o in suitable relation to the conductor, substandescribed 'arranged in operative relation to tially as set forth. the conductor, substantially as set forth.

. 19. A grounded conductor for Wireless te- In testimony whereof I have hereunto set 5 legraphy,in combination With a movable piece my hand. of conducting material arranged on the eon- REGINALD A. FESSENDEN.

ductor, substantially as set forth. W'itnesses:

20. A combination of a vertically-arranged W. B. FEARING,

grounded conductor for radiating electromag- S. C. GRAY. 

